Electromagnetic impact vibrator



July .25, 1967 SHINOBU MAKINO 3,333,219

ELECTROMAGNETIC IMPACT VIBRATOR Filed Sept. 22, 1965 5 Sheets-Sheet l IZb i4 FIG.

July 25, 1967. SHINOBU MAKINO 3,333,219

ELECTROMAGNETIC IMPACT VIBRATOR Filed Sept. 22, 1965 3 Sheets-Shee 2 FIG. 5

45 47 57 25; 748 FIG. 7

July 25, 1967 SHINOBU MAKINO 3,333,219

ELECTROMAGNETIC IMPACT VIBRATOR Filed Sept. 22, 1965 C5 Sheets-Sheet 5 Ill-HIM mu FIG. 6

United States Patent 3,333,219 -ELECTROMAGNETIC IMPACT VIBRATOR Shinobu Makino, Tokyo, Japan, assigncr to Shinko Electric Company, Ltd., Tokyo, Japan Filed Sept. 22, 1965, Ser. No. 489,287 Claims priority, application Japan, Apr. 2, 1%5,

0/19,440 19 Claims. (Cl. 335-252) This invention relates generally to impact vibrators and more particularly to electromagnetic impact vibrators.

Known electromagnetic impact vibrators are provided with steel leaf springs for effecting vibrations and usually have spaced dual impact members which have a width substantially equal to the length of the springs. Other known electromagnetic vibrators are provided with elastomers for vibration and generally have an impact member or part at a lower end of a cylindrical armature. The impact member is generally circular and has a diameter which is as large as that of the armature. Thus in the known impact vibrators, the impact member cannot impact orimpart energy at the same time over all of the contacting surface of the impact member. This results in an irregularity of vibration and inefiiciency of development of the vibrations of the vibratory apparatus.

A principal object of the invention is to provide a new and improved impact vibrator which has only one impact member receiving aconcentrated vibratory force over the entire impact surface thereof, from a movable armature which is coaxial with the impact member and applies impact vibratory forces along the longitudinal axis of the impact thereby eliminating irregularity of vibration, and highly efiicient development of vibrations.

Another object of the present invention is to provide a vibratory system operable in a principal mode of vibration and to provide an improved combination in a vibratory system with an improved armature.

Still another object of the invention is to provide an impact vibrator having a very simple construction.

A feature of the electromagnetic impact vibrator according to the invention is the provision, in combination, of mounting means for mounting the vibrator on a surface to which the vibrations are to be imparted and an impact member fixed relative to the base for receiving periodic impacts from a new vibratory system thereby vibrating the vibrator. The improved vibratory system is operable in a principal mode of vibration for periodically inspecting the impact member and comprises an armature vibratable toward the impact member for periodically impacting it. Electromagnetic means are provided periodically attracting the armature to an operative position in which it engages and impacts the impact member and includes concentric pole pieces one of which is cup-shaped and internally of which is disposed and coaxially therewith an exciting coil.

The vibratory system includes an elastic element having the form of an annular elastomer mounting the armature in a rest position spaced from the impact member, defining an air gap therewith, and effective to permit movement of the armature for impacting the impact member when the exciting coil is energized. The elastomer restores the armature to its normal or rest position spaced from the impact member subsequent to each impact of the armature on the impact member. In preferred constructions the elastic element or elastomer is mounted concentric with the impact member and the armature. The armature is providedwith an impact surface capable of applying an impact force to the impact member generally, axially of the impact member and substantially over all of an end contact surface.

' bodiment of an electromagnetic vibrator according to the Other features and advantages of the electromagnetic impact vibrator according to the invention will be better understood as described in the following specification and appended claims, in conjunction with the following drawings in which:

FIG. 1 is a side elevation sectionview of an'embodiment of an electromagnetic impact vibrator according to the invention;

FIG. 2 is a section view taken along section line 2-2 of FIG. 1; 7

FIG. 3 is a side elevation section view of another embodiment of the invention;

' FIG. 4 is a section view taken along section line 4-4 of FIG. 3;

' FIG. 5 is a side elevation section view of a third embodiment of an electromagnetic impact vibrator according to the invention;

FIG. 6 is a section View taken along section line 6-6 of FIG. 5;

FIG. 7 is a side elevation section view of a fourth embodiment of an electromagnetic impact vibrator embodying the invention;

FIG. 8 is a side elevation section view of a fifth eminvention; and

. FIG. 9 is a diagrammatic view of an impact vibrator according to the invention mounted on a hopper for illustrating operation of a vibrator embodying the invention. A first embodiment of the invention is illustrated in FIGS. 1 and 2. The drawings illustrate an electromagnetic impact vibrator 1 having a base 2 for mounting the vibrator on a surface to which vibration isto be imparted, for example, for mounting on a hopper, as later described, with mounting bolts or other fasteners extending through a plurality of openings 3. A central, upstanding magnetic pole piece 4 made of steel, for example a low carbon steel, is provided and has an extension for mounting the pole piece in a fixed condition to the base 2 as hereinafter described. An outer magnetic pole piece which is bowl-shaped or cup-shaped is disposed concentric with the fixed pole'piece 4 and is likewise secured by rivets 6 to the base 2. The upstanding pole piece 4 extends axially through a central opening in the outer pole piece and is provided with an extension 7 extending through the base 2 and has a lower end threaded and secured to the base I 2 with a nut 8.

i filling or plastic material 10 filling the spaces between the exciting coil 9 and the outer pole 5. The plastic material 10 need not completely fill the outer pole piece so that the upstanding central pole piece 4 extends slightly higher than the upper edge defining the opening of the outer pole piece and higher than the filling material as illustrated for receiving impacts as hereinafter described.

In order to impact the central pole piece 4 which func tions as an impact member, the vibratory system comprises an armature 11 which is shaped in the manner of an inverted bowl having its central portion coaxial with the central pole piece'and substantially disposed coaxial with the outer pole piece. The armature 11 has downwardly extending sidewalls 11a to which is bonded, with a bonding agent layer 12a, an annular, elastic element 12 comprising an elastomer having its inner surfaces likewise bonded by a bonding layer 12b. The annular elastic member is concentric with the pole pieces and holds the armature inner bottom surface axially spaced from the upper end surface of the impact member 4, for example, a few 3 millimeters in an initial operative position and thereby defining an air gap G. When the exciting coil 9 is electrically energized by alternating current or pulsating direct current the armature 11 is periodically actuated in a direction toward the upper, impact surface of the member 4 and strikes it effectively vibrating the vibrator. During the operation flux lines flow along magnetic circuits or paths 15, 16. This fiux builds up and collapses when the exciting coil is energized with alternating current or a pulsating direct current. When the flux lines build up the armature is actuated and when they collapse the elastic member 12 restores the armature 11 to its initial position spaced from the impact member so that periodic excitation of the coil 9 will cause the armature to periodically impact the impact member 4 thereby generating the vibrations.

It can be seen that the armature and elastic member secured thereto form a vibratory system which can be tuned so that it has a natural frequency substantially resonant within a few cycles of the frequency of the electric alternating or pulsating current applied to the exciting coil 9. The upper end of the impact member 4 is a relatively small circular portion as illustrated in FIG. 4 and the body of the armature has its center of gravity coaxial therewith and impact will occur over all of the impact surfaces even if the armature happens to be supported slightly sloped relative to the longitudinal axis of the impact upstanding member 4 as later explained. Therefore the vibrator will generate vibrations with higher efiiciency than is possible in known vibrators.

A second embodiment of an electromagnetic impact vibrator according to the invention is illustrated in FIGS. 3 and 4. As illustrated in FIG. 3, a vibrator is provided with a base 21 provided with openings 23 for mounting the vibrator on a surface to which vibrations are to be imparted. An upstanding central impact member 24 is provided with an extension 25 which extends through the base and has its outer end threaded and is secured or fixed with a nut 26 to the base 21. The impact member is disposed internally of a tubular inner pole Piece 28. An exciting coil 29 is wound coaxially with the center pole piece 28 and is electrically energized periodically as before described relative to the first embodiment from a source of power not shown. The exciting coil '29 is circumferentially enclosed by a bowl-shaped outer pole piece 30 disposed coaxially with the central pole piece and having binding or filling 31 holding the coil secured therein and is mounted in a fixed condition to the base 21 with rivets 33. The impact member extends through a central opening in the outer pole piece- The vibratory system of the second embodiment comprises a movable bowl-shaped armature 34 disposed in an inverted position and is provided with an annular, elastic member 35 functioning similarly to the annular, elastic, member 12 in the first embodiment. In the second embodiment the central impact member is made of steel or brass and is somewhat shorter axially than the inner and outer pole pieces and is provided with an impact surface provided by an elastic plate 36, made, for example, of a plastic. In the instant example of the invention, the armature 34 may be made one millimeter thick and an air gap defined between the upper surface of the impact plate 36 and the inner surface of the armature may be in the order of two millimeters. In this construction the upper or end face of the center and outer pole pieces are protected from damage upon impact by impacting an elastic plate 36 without sacrificing any efiiciency of the vibrator. The impact forces are not decreased even though applied to the elastic member 36 since the thickness of this member 36 need not be very great, for example in the order of three millimeters, and the gap dimensions between the armature and it need not be greater than is used in the first described embodiment.

A third embodiment of a vibrator is illustrated in FIGS. 5 and 6. The vibrator illustrated comprises a base 41 having an upwardly extending integral projection 42 which provides the impact member through which the vibrations are applied by the vibratory system of this embodiment. In this construction a central pole piece 44 is made of wound silicon steel sheet as multiple, concentric layers disposed coaxial with the impact member. This construction avoids eddy current losses in the central pole piece since it is made, in effect, of laminations. An outer pole piece 45 is disposed coaxial or concentric with the inner pole and has a central opening through which the impact member 42 extends upwardly. An exciting coil 47 is provided internally of the outer pole piece which is filled with a suitable filling 48 holding the coil fixed relative to the pole pieces as before described in the other embodiments.

The vibratory system in this embodiment comprises an armature 49 which is formed as an inverted bowl and has an inner, annular, support member 50 secured thereto with rivets 51. A second, inner annular, support member 52 is secured to the base by rivets 53. These annular members jointly hold an elastic member 54 having its inner and outer surfaces bonded to the two annular members 50, 52 movably mounting the armature 49 as before described and spaced from the impact member defining an air gap in its rest or normal operative position for effecting impacts when the exciting coil 47 is energized through connections from a source not shown. In this construction the impact member 42 has less axial length than the pole pieces and an elastic impact piece or plate 55 made of an elastic material and functioning in a man ner as before described.

In an embodiment of a vibrator illustrated in FIG. 7, the construction is the same as that described relative to FIGS. 5 and 6 as to substantially all of the members and the corresponding members are illustrated with similar reference numerals as the construction in FIG. 5 except that the references are primed. In this embodiment the inner surface of an armature 49 is provided with magnetic l aminations 56 secured by rivets 57 as illustrated in FIG. 7. The impact surface of the armature as defined by the laminations comprises punched circularshaped silicon steel sheets which are secured to the inner side of the armature and dimensioned so that the laminations extend substantially over the inner surface sufficiently to provide a magnetic path for flux passage in conjunction with the inner and outer pole pieces thereby greatly reducing losses in the armature.

A final embodiment of a vibrator is illustrated in FIG. 8 in which a vibrator 59 is provided with a base 60 for mounting having an integral upstanding central portion 61 providing the impact member to which the impactions are applied for vibrating the base 60 thereby to vibrate a surface on which the vibrator is mounted. In this construction a laminated central or center pole piece 62 cooperates with an outer pole piece 63 in developing flux or magnetic lines of force when an exciting coil 64 is energized as before described. The coil 64 is held by a suitable binder or filling 65 substantially fiush with the upper edge surfaces of the pole pieces as illustrated. As armature 66 is held axially spaced defining an air gap between the upper impact surfaces of an elastic member 68 mounted on the upper end of impact member 61. The armature is movably held in position by an elastic, annular member comprising an elastomer 71 having its inner surface bonded to the outer periphery of the armature and an outer surface bonded to an annular support member 72 fixed to the base with body bolts 73. The fiux path or magnetic circuit in this construction of the electromagnetic means activating the vibratory system is improved by provision of laminations 75, made for example of a silicon steel, secured to the inner surface of the armature 66 with rivets 76. This device functions in developing vibrations as before described when the coil 64 is energized.

Those skilled in the art will understand that in each instance the vibratory system of the various vibrators described has the center of gravity of each of the armatures substantially coaxial with the longitudinal axis of the impact member which is upstanding. The effective impact surface of the armature is greater than the impact surface of the impact member receiving the impacts of the armature periodically. Even though the armature is not mounted in operation substantially in position for the impact surface thereof to strike, the impact surface of the impact member flush with and even though mounted somewhat canted due to surface on which the vibrator is mounted, the elastomer member of the vibratory system provides for impacts in Whichthe impact surfaces meet substantially completely flush over the entire surface. Moreover, the vibratory system can be easily tuned to substantially the value, within a few cycles, of the exciting current, whether alternating or pulsating input direct current.

The improved operation of a vibratory system of a vibrator according to the invention is diagrammatically illustrated in FIG. 9 in which is illustrated a vibrator mounted on a very sloped sidewall surface 90 of a hopper 91 which is to be vibrated, for example, to deliver contents thereof through a bottom opening 92. The vibr-ator is fragmentarily shown and the vibratory system and impact member are readily recognizable as an armature and elastomer bonded thereon. As can be seen, the center of gravity X of the vibratory system is coaxial with the center of gravity Y of the impact member and an elastic impact plate mounted thereon. The effect of gravity on the vibrator is illustrated by downwardly extending arrows 94, 95. The elastomer holding the armature spaced from the impact surface permits the armature to be movably mounted with a minimum change in the magnetic circuits of the apparatus. It can be seen that a change in the gap between the central portion of the armature and the central pole piece will necessarily be very small and the length of the flux lines remains about the same since any change between the armature position, which defines the flux path, and the outer pole is compensated by the fact that the gap between the outer pole piece and the armature increases :at the upper end of the armature but decreases a corresponding distance at the lower end of the armature. The electromagnetic means, therefore, remains as effective as ever and impacts will be effected completely across the contacting impact surfaces. Thus the efficiency of the apparatus remains undisturbed when mounted on a decided incline as illustrated. v

In preferred embodiments of the invention the various teachings of the illustrations disclosed are combined. Thus preferably the pole pieces have a lesser axial length than a separate impact member so that the pole pieces are not impacted. Moreover, the magnetic circuit is provided by use of magnetic laminations in the armature and concentric wound layers of magnetic material in the central pole piece thereby to reduce eddy current losses in the magnetic path. The use of a magnetic path independent of the impact member and the armature allows the armature and impact member to be made of non-magnetic material. Furthermore, the impact member can be made integral with the base or made independently of the base and fixed thereon.

The armature may be preferably made as a simple disc as illustrated in FIG. 8 and the support of the armature and elastomer disposed radially outwardly independently of the outer pole piece so that minimum distortion of the gaps G and G takes place.

While preferred embodiments of the invention have been shown :and described, it will be understood that many modifications and changes can be made within the true spirit and scope of the invention.

What I claim and desire to secure by Letters Patent is:

1. An electromagnetic impact vibrator comprising, a base for mounting said vibrator on a surrface to which vibration is to be imparted, means comprising an impact member fixed relative to said base and including an impact surface for receiving periodic impacts for vibrating said vibrator, a vibratory system operable in a principal mode of vibration for periodically impacting said impact member comprising an armature having a magnetizable portion and disposed vibratable toward said impact member for periodically impacting it, electromagnetic means periodically attracting said armature to an operative position in which it engages and impacts said impact member, an annular elastic element mounting said armature in a rest position spaced from said impact member and restoring said armature toward said rest position subsequent to each impact of said armature on said impact member.

2. An electromagnetic impact vibrator according to claim 1, in which said armature and said :annular element and said impact surface are coaxial.

3. An electromagnetic impact vibrator according to claim 2, in which said impact surface comprises an elastic surface.

4. An electromagnetic impact vibrator according to claim 1, in which said electromagnetic means comprising, a pair of concentric pole pieces defining in conjunction with said magnetizable portion of said armature 'a magnetic flux path, and a coil for developing periodically magnetic flux in said path to periodically attract said armature to said operative position. 5. An electromagnetic impact vibrator according to claim 4, in which said impact member comprises one of said pole pieces, said pole pieces being disposed coaxially with said armature and said annular elastic element.

6. An electromagnetic impact vibrator according to claim 4, in which said pole pieces are disposed coaxial with said annular elastic member and said armature.

7. An electromagnetic impact vibrator according to claim 1, in which said electromagnetic means comprises coaxial pole pieces, an electrically energizable coil for developing flux periodically attracting said armature toward said impact member, said impact member being disposed coaxial with said pole pieces, said elastic element and said armature being disposed coaxial relative to each other and coaxial relative to said impact member for vibration in an operational mode generally coaxially with said impact member.

8. An electromagnetic impact vibrator according to claim 1, in which said impact member is an elongated member and in which said impact member and said armature have the center of gravity thereof substantially coaxial, said elastic element mounting said armature for vibration in a principal mode coaxially with the longitudinal axis of said mpact member thereby to apply and impact force to said impact member generally axially of said impact member.

9. An electromagnetic impact vibrator comprising, a base for mounting the vibrator, impact means comprising an elongated impact member fixed relative to said base and upstanding relative thereto, for receiving periodic impacts vibrating said vibrator, a electromechanical vibratory system for periodically impacting said impact member comprising an armature coaxial with said impact member and vibratable toward said impact member for periodically impacting said impact member, said armature having a magnetizable portion, electromagnetic means periodically attracting said armature to an operative position in which it engages and impacts said impact member, said electromagnetic means comprising pole piece means coaxial with said impact member, a coil electrically energizable for developing magnetic flux in said pole piece means periodically attracting said armature magnetizable portion and into engagement with said impact means comprising an annular, elastic element comprising an elastomer material elastically mounting said armature in a rest position spaced from said impact member coaxially with said impact member and effective to restore said armature toward said rest position subsequent to each impact of said armature on said impact member.

10. An electromagnetic impact vibrator according to claim 9, in which said magnetizable portion of said armature comprises a plurality of laminations of a magnetic material secured on said armature.

11. An electromagnetic impact vibrator according to claim 9, in which said pole piece means comprises a pair of coaxial pole pieces comprising a tubular, cylindrical inner pole piece coaxial with said impact member, said impact member being disposed internally of said inner pole piece.

12. An electromagnetic impact vibrator according to claim 11, in which said inner pole piece comprises a plurality of coaxial layers of a magnetizable material wound circumferentially of said impact member.

13. An electromagnetic vibrator according to claim 9, in which said impact means comprises elastic means defining an impact surface disposed for receiving impacts from said armature substantially axially of said elongated impact member.

14. An electromagnetic vibrator according to claim 9, in which said magnetizable portion on said armature comprises laminations of a magnetizable material fixed opposite to said impact means defining an air gap jointly therewith, said pole piece means and said laminations disposed defining a magnetic circuit.

15. An electromagnetic vibrator according to claim 14, in which pole piece means comprises a bowl-shaped outer pole piece containing said coil and an inner elongated pole piece comprising wound layers of a magnetizable material. 1

16. An electromagnetic vibrator according to claim 14, in which said armature comprises a circular disk, and including tubular means disposed outwardly of said armature mounting said elastic element internally thereof, said disk being bonded to internal surfaces of said annular elastic element.

17. An electromagnetic vibrator according to claim 9, in which said pole piece means comprises a bowl-shaped outer pole piece and an inner pole piece, said coil being mounted internally of said outer pole piece and circumferentially of said inner pole piece, said annular elastic element being disposed circumferentially of said center pole piece and secured thereto, and said armature having surfaces secured to the periphery of said elastic element for mounting thereon. V

18. An electromagnetic impact vibrator according to claim 17, in which said magnetizable portion on said armature comprises la-minations and in which said inner pole piece comprises a plurality of concentric layers of a material defining a magnetic flux path jointly with said outer pole piece and said laminations.

19. An electromagnetic impact vibrator according to claim 9, in which vibratory system is dimensioned to have a natural resonance frequency corresponding and substantially tuned to a frequency of a current energizing said coil during operation.

References Cited UNITED STATES PATENTS 6/1948 Hittson 310 3/1959 Toulmin 31030 X 

1. AN ELECTROMAGNETIC IMPACT VIBRATOR COMPRISING, A BASE FOR MOUNTING SAID VIBRATOR ON A SURFACE TO WHICH VIBRATION IS TO BE IMPARTED, MEANS COMPRISING AN IMPACT MEMBER FIXED RELATIVE TO SAID BASE AND INCLUDING AN IMPACT SURFACE FOR RECEIVING PERIODIC IMPARTS FOR VIBRATING SAID VIBRATOR, A VIBRATORY SYSTEM OPERABLE IN A PRINCIPAL MODE OF VIBRATION FOR PERIODICALLY IMPACTING SAID IMPACT MEMBER COMPRISING AN ARMATURE HAVING A MAGNETIZABLE PORTION AND DISPOSED VIBRATABLE TOWARD SAID IMPACT MEMBER FOR PERIODICALLY IMPACTING IT, ELECTROMAGNETIC MEANS PERIODICALLY ATTRACTING SAID ARMATURE TO AN OPERATIVE POSITION IN WHICH IT ENGAGES AND IMPACTS SAID IMPACT MEMBER, AN ANNULAR ELASTIC ELEMENT MOUNTING SAID ARMATURE IN A REST POSITION SPACED FROM SAID IMPACT MEMBER AND RESTORING SAID ARMATURE TOWARD SAID REST POSITION SUBSEQUENT TO EACH IMPACT OF SAID ARMATURE ON SAID IMPACT MEMBER. 